Optical encoder
Summary by NHIP
Parallel optical encoder with bearing surface
The optical encoder determines code strip position using a light source and detector separated by a space for the strip to move through. A bearing surface slidably engages the strip to maintain spacing alignment between the parallel light source and detector within a housing.
Claim Score by NHIP
Abstract
An optical encoder includes a code strip having a first side, a second side, a first track comprising indicia thereon, and a second track comprising indicia thereon. The code strip is moveable along a displacement path with respect to the optical encoder. A light source positioned on the first side of the code strip directs light toward the code strip. A first detector element is positioned on the second side of the code strip and is generally aligned with the first track of the code strip. A second detector element is positioned on the second side of the code strip and is generally aligned with the second track of the code strip. The second detector element is also positioned so that the second detector element is located a spaced distance along the displacement path from the first detector element.

Term
Term ended
Expired 7 January 2025, 1.7 years ago.
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14 claims: 2 independent, 12 dependent
- 1Broadest claimClaim Score 53, average(NHIP)An optical encoder for determining a position of a code strip with respect to said optical encoder, the code strip having indicia provided thereon, comprising:a light source;a detector positioned in spaced-apart relation from said light source so that a space is defined between said light source and said detector, said space being adapted to receive the code strip and allow the code strip to be moved along a displacement path with respect to said optical encoder;an aperture plate positioned adjacent said detector so that said aperture plate is between said detector and the code strip when the code strip is received within the space defined between said light source and said detector, said aperture plate defining an aperture therein that is substantially aligned with said detector so that said detector detects indicia on the code strip;and a housing, said housing being adapted to receive said detector and said light source in generally parallel, spaced-apart relation, said housing defining a bearing surface, said bearing surface slidably engaging the code strip when the code strip is positioned in the space defined between said detector and said light source, said bearing surface maintaining a spacing alignment of the code strip within the space defined between said detector and said light source as the code strip moves along the displacement path.
- 5An optical encoder, comprising:a code strip, said code strip having a first side, a second side, at least one substantially transparent area thereon, and at least one substantially opaque area thereon;a light source positioned the first side of said code strip, said light source directing light toward said code strip;a detector positioned on the second side of said code strip, said detector being substantially aligned with said light source;an aperture plate positioned between said detector and the second side of said code strip, said aperture plate defining a slit aperture therein, said slit aperture being aligned with said detector so that light passing through the at least substantially one transparent area of said code strip reaches said detector;and a housing, said housing being adapted to receive said detector and said light source in generally parallel, spaced-apart relation, said housing defining a bearing surface, said bearing surface slidably engaging said code strip when said code strip is positioned in a space defined between said detector and said light source, said bearing surface maintaining a spacing alignment of said code strip within the space defined between said detector and said light source.
Independent claims2
47 paragraphs in 5 sections, as filed
CROSS-REFERENCE TO RELATED APPLICATIONS
0001This is a divisional of application Ser. No. 11/031,280, filed on Jan. 7, 2005 , now U.S. Pat. No. 7,244,928 the entire disclosure of which is incorporated into this application by reference.
BACKGROUND
0002Position and/or motion encoders provide a means for determining the position and/or motion of moveable components. While a wide variety of position encoder systems have been developed and are being used, most position encoder systems can be placed into one of two categories: linear and rotary. As their respective names imply, linear encoder systems may be used to provide an indication of linear or straight-line motion whereas rotary encoders may be used to provide an indication of rotary motion.
0003Encoder systems of the type described above may be further characterized as analog encoder systems or digital encoder systems. Analog encoder systems provide an analog output signal, such as a voltage or current that is related to the motion detected by the encoder. Analog encoder systems typically utilize a variable resistor or resistance element that is operatively associated with the moveable element. The variable resistor converts the motion of the moveable component into the analog signal.
0004Digital encoder systems provide a digital output signal that is related to the motion detected by the encoder. Most digital encoder systems are optical in nature, although non-optical digital encoders are also known. An optical digital encoder typically utilizes a light source, a detector, and a code wheel or code strip. The code wheel or code strip is provided with markings or indicia thereon. The detector detects the indicia provided on the code wheel or code strip and produces a digital output signal that is related to the position or movement of the code strip with respect to the detector.
0005Digital encoders may provide a relative or absolute indication of the relative position of the code wheel or code strip. Generally speaking, relative encoders provide a single set of markings or indicia on the code strip. Because the single set of markings is not unique to the particular position of the code strip, relative encoder systems must utilize a homing routine on start-up in order to derive the actual position of the moveable component. Absolute position encoders typically rely on several sets of indicia on the code strip. The indicia are such that a unique signal is associated with each position of the code strip. Thus, such absolute position encoders can provide an indication of the absolute position of the moveable element without the need to first perform a homing routine.
SUMMARY OF THE INVENTION
0006An optical encoder according to one embodiment may comprise a code strip having a first side, a second side, a first track comprising indicia thereon, and a second track comprising indicia thereon. The code strip is moveable along a displacement path with respect to the optical encoder. A light source positioned on the first side of the code strip directs light toward the code strip. A first detector element is positioned on the second side of the code strip and is generally aligned with the first track of the code strip. A second detector element is positioned on the second side of the code strip and is generally aligned with the second track of the code strip. The second detector element is also positioned so that the second detector element is located a spaced distance along the displacement path from the first detector element.
BRIEF DESCRIPTION OF THE DRAWINGS
0007Illustrative and presently preferred exemplary embodiments of the invention are shown in the drawings in which:
0008<figref idref="DRAWINGS">FIG. 1</figref> is a perspective view of one embodiment of an optical encoder;
0009<figref idref="DRAWINGS">FIG. 2</figref> is an exploded perspective view of the optical encoder of <figref idref="DRAWINGS">FIG. 1</figref>;
0010<figref idref="DRAWINGS">FIG. 3</figref> is a side view in elevation of the optical encoder of <figref idref="DRAWINGS">FIG. 1</figref>;
0011<figref idref="DRAWINGS">FIG. 4</figref> is a plan view of the light source assembly of the optical encoder of <figref idref="DRAWINGS">FIG. 1</figref>;
0012<figref idref="DRAWINGS">FIG. 5</figref> is an exploded perspective view of the light source assembly of <figref idref="DRAWINGS">FIG. 4</figref>;
0013<figref idref="DRAWINGS">FIG. 6</figref> is a plan view of the detector assembly of the optical encoder of <figref idref="DRAWINGS">FIG. 1</figref>;
0014<figref idref="DRAWINGS">FIG. 7</figref><i>a </i>is a side view in elevation of a portion of the housing of the optical encoder of <figref idref="DRAWINGS">FIG. 1</figref>;
0015<figref idref="DRAWINGS">FIG. 7</figref><i>b </i>is an enlarged side view of a portion of the housing more clearly showing one of the bearing surfaces of <figref idref="DRAWINGS">FIG. 7</figref>; and
0016<figref idref="DRAWINGS">FIG. 8</figref> is a plan view of the housing of <figref idref="DRAWINGS">FIG. 7</figref> showing the positions of the bearing surfaces.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
0017One embodiment of an optical encoder <b>10</b> is shown in <figref idref="DRAWINGS">FIGS. 1 and 2</figref> and comprises a code strip <b>12</b> having a first side <b>14</b> and a second side <b>16</b>. The code strip <b>12</b> comprises a plurality of tracks <b>17</b> with indicia <b>19</b> provided thereon, such as a first track <b>18</b> of indicia <b>20</b> and a second track <b>22</b> of indicia <b>24</b>. As will be described in greater detail below, the code strip <b>12</b> may be provided with any number of tracks <b>17</b> of indicia <b>19</b> thereon, depending on a number of factors, including, but not limited to, the desired resolution and the range of motion to be encoded. The code strip <b>12</b> is moveable along a displacement path <b>26</b> with respect to the optical encoder <b>10</b>. In the embodiment shown and described herein, a read head <b>28</b> of the optical encoder <b>10</b> is moveable with respect to the code strip <b>12</b>, which remains stationary. Alternatively, the code strip <b>12</b> could be moveable, with the read head <b>28</b> remaining stationary.
0018With reference now primarily to <figref idref="DRAWINGS">FIG. 2</figref>, the optical encoder <b>10</b> may also be provided with a light source assembly <b>30</b> and a detector assembly <b>32</b>. The light source assembly <b>30</b> and detector assembly <b>32</b> may be mounted to a housing assembly <b>34</b>. Thus, the read head <b>28</b> comprises the light source assembly <b>30</b>, detector assembly <b>32</b>, and the housing assembly <b>34</b>. The arrangement is such that the light source assembly <b>30</b> is positioned on the first side <b>14</b> of the code strip <b>12</b>, whereas the detector assembly <b>32</b> is positioned on the second side <b>16</b> of the code strip <b>12</b>. The detector assembly <b>32</b> is also generally aligned with the light source assembly <b>30</b>, so that light produced by the light source assembly <b>30</b> and passing through the code strip <b>12</b> can be detected by the detector assembly <b>32</b>.
0019The light source assembly <b>30</b> is shown in <figref idref="DRAWINGS">FIGS. 4 and 5</figref> and may comprise a plurality of light emitting elements <b>37</b>, such as, for example, a first light emitting element <b>38</b> at a first location along the displacement path <b>26</b> and a second light emitting element <b>40</b> at a second location along the displacement path <b>26</b>. In the embodiment shown and described herein, the light source assembly <b>30</b> is provided with additional light emitting elements, as will be described in greater detail below. Each of the plurality of light emitting elements <b>37</b> is provided with a corresponding collimating lens <b>41</b>, such as first collimating lens <b>42</b> and second collimating lens <b>44</b>. The various light emitting elements <b>37</b> are positioned in various locations to form the staggered spacing arrangement shown in <figref idref="DRAWINGS">FIG. 4</figref>. More specifically, in one embodiment, the first light emitting element <b>38</b> is positioned along a first light emitting element axis <b>46</b>, whereas the second light emitting element <b>40</b> is positioned along a second light emitting element axis <b>48</b>. The first and second light emitting element axes <b>46</b> and <b>48</b> are separated by a spaced-distance <b>50</b> along the direction of the displacement path <b>26</b>. As will be explained in greater detail below, this staggered spacing of the first and second light emitting elements <b>38</b> and <b>40</b> allows the overall length <b>48</b> of the light source assembly <b>30</b> to be reduced compared to what would otherwise be the case if the individual light emitting elements <b>37</b> (e.g., first light emitting element <b>38</b> and second light emitting element <b>40</b>) were aligned along a common axis.
0020The detector assembly <b>32</b> is best seen in <figref idref="DRAWINGS">FIG. 6</figref> and may comprise a plurality of detector elements <b>51</b>, such as a first detector element <b>52</b> positioned at a first location along the displacement path <b>26</b> and a second detector element <b>54</b> positioned at a second location along the displacement path <b>26</b>. In the embodiment shown and described herein, the detector assembly <b>32</b> is provided with additional detector elements <b>51</b>, as will be explained in greater detail below. The first detector element <b>52</b> is positioned along a first detector element axis <b>56</b>, whereas the second detector element <b>54</b> is positioned along a second detector element axis <b>58</b>. The first and second detector element axes <b>56</b> and <b>58</b> are separated by a spaced-distance <b>60</b> along the direction of the displacement path <b>26</b>. In one embodiment, the spaced-distance <b>60</b> separating the first and second detector element axes <b>56</b> and <b>58</b> is substantially equal to the spaced-distance <b>50</b> between the first and second light emitting element axes <b>46</b> and <b>48</b> (<figref idref="DRAWINGS">FIG. 4</figref>).
0021In addition, the first detector element <b>52</b> is generally aligned with the first track <b>18</b> of the code strip <b>12</b> so that the first detector element <b>52</b> detects the indicia <b>20</b> comprising the first track <b>18</b> of code strip <b>12</b>. The second detector element <b>54</b> is generally aligned with the second track <b>22</b> of code strip <b>12</b> so that the second detector element <b>54</b> detects the indicia <b>24</b> comprising the second track <b>22</b> of code strip <b>12</b>.
0022The staggered spacing of the various detector elements (e.g., <b>52</b> and <b>54</b>) comprising the detector assembly <b>32</b>, that is to say, the fact that the second detector element <b>54</b> is located the spaced-distance <b>60</b> along the displacement path <b>26</b> from the first detector element <b>52</b>, means that the indicia <b>24</b> comprising the second track <b>22</b> of the code strip <b>12</b> should be displaced or off-set by substantially the same distance, i.e., the spaced-distance <b>60</b>.
0023The optical encoder <b>10</b> may also be provided with an aperture plate <b>62</b>. The aperture plate <b>62</b> is positioned between the detector assembly <b>32</b> and the code strip <b>12</b> in the manner best seen in <figref idref="DRAWINGS">FIG. 3</figref>. The aperture plate <b>62</b> defines at least a first aperture <b>64</b> that is generally aligned with the first detector element <b>52</b> and a second aperture <b>66</b> that is generally aligned with the second detector element <b>40</b>. The aperture plate <b>62</b> may be provided with additional apertures, as will be described in greater detail below. In addition, and as will also be described in greater detail below, the aperture plate <b>62</b> may in some cases provide for increased resolution of the optical encoder <b>10</b>.
0024One useful feature of the optical encoder <b>10</b> is that it is readily scalable, thus allowing it to be easily adapted to a wide range of applications. That is, the same basic design can be easily modified by either increasing or decreasing the number of individual light emitting elements <b>37</b> and detector elements <b>51</b> to accommodate wider or narrower code strips. Another useful feature of the optical encoder <b>10</b> is that the staggered arrangement of the light emitting elements <b>37</b> allows the overall length <b>49</b> of the light source assembly <b>30</b> to be reduced over what would otherwise be the case if the staggered spacing were not used. In addition, the use of separate or staggered collimating lenses <b>41</b> for each light emitting element <b>37</b> allows the overall thickness of the read head <b>28</b> to be reduced over what would be otherwise required if a single collimating lens were used for all of the light emitting elements <b>37</b>. The aperture plate <b>62</b> provides for increased sensitivity by limiting the amount of stray light that is allowed to reach the various detector elements <b>51</b>. The aperture plate <b>62</b> may also provide for increased resolution of the optical encoder.
0025Having briefly described one embodiment <b>10</b> of an optical encoder, this and other embodiments will now be described in greater detail. However, before proceeding, it is noted that the optical encoder <b>10</b> may be provided with any of a wide range of separate light emitting elements <b>41</b> and detector elements <b>51</b>, depending on its application. In addition, the number of tracks <b>17</b> provided on the code strip <b>12</b>, as well as the number and spacing of the indicia <b>19</b> that may be provided on each track may also vary depending on the requirements of the particular application as well as the desired resolution. Similarly, the optical encoder is not limited to use in linear applications and could be readily adapted for use in rotary applications, as would become apparent to persons having ordinary skill in the art after having become familiar with the teachings provided herein.
0026Referring back now to <figref idref="DRAWINGS">FIGS. 1 and 2</figref>, one embodiment of an optical encoder <b>10</b> may be used to determine an absolute position of a code strip <b>12</b> relative to a read head <b>28</b> of the optical encoder <b>10</b>. In the embodiment shown and described herein, the read head <b>28</b> moves along a displacement path <b>26</b> with respect to the code strip <b>12</b>, which remains stationary. Alternatively, the code strip <b>12</b> could be moveable, with the read head <b>28</b> remaining stationary. Likewise, the code strip <b>12</b> need not comprise a generally rectangularly shaped element, but could instead comprise a disk-like or annular member for use in rotary applications.
0027In order to provide absolute position sensing, the code strip <b>12</b> is provided with a plurality of tracks <b>17</b> (e.g., a first track <b>18</b> and a second track <b>22</b>) having indicia <b>19</b> (e.g., first set of indicia <b>20</b> and second set of indicia <b>24</b>) provided thereon. The indicia <b>19</b> are detectable by the detector assembly <b>32</b> in order to allow the detector assembly <b>32</b> to detect movement of the code strip <b>12</b>. Commonly used indicia <b>19</b> include, but are not limited to, alternating regions that are substantially transparent and substantially opaque to the light produced by the light source assembly <b>30</b>. Adjacent tracks <b>17</b> are provided with differing indicia to allow the absolute position of the code strip <b>12</b> to be determined relative to the read head <b>28</b>. For example, in one embodiment each successive track <b>17</b> is provided with twice the number of indicia (e.g., substantially transparent and substantially opaque regions), thereby allowing each position along the code strip <b>12</b> to have a unique “code” associated therewith.
0028One feature of the code strip <b>12</b> that is unique relates to those tracks <b>17</b> that correspond to the detector elements <b>51</b> (e.g., second detector element <b>54</b>) that are located at the off-set or displaced position along the displacement path <b>26</b>, such as those detector elements <b>51</b> that are arranged along the second detector element axis <b>58</b>. As mentioned, the indicia <b>19</b> (e.g., indicia <b>24</b>) of those tracks corresponding to the off-set detectors (e.g., second track <b>22</b>) should be off-set by the same spaced-distance (e.g., spaced-distance <b>60</b>) separating the detector elements <b>51</b>.
0029Referring now to <figref idref="DRAWINGS">FIGS. 4 and 5</figref>, the light source <b>30</b> may comprise a plurality of individual light emitting elements <b>37</b>, such as a first light emitting element <b>38</b> and a second light emitting element <b>40</b>. Each of the plurality of light emitting elements <b>37</b> is provided with a corresponding collimating lens <b>41</b>, such as first collimating lens <b>42</b> and second collimating lens <b>44</b>. The first light emitting element <b>38</b> is positioned along a first light emitting element axis <b>46</b>, whereas the second light emitting element <b>40</b> is positioned along a second light emitting element axis <b>48</b>. In the embodiment shown and described herein, the light source assembly <b>30</b> is provided with additional light emitting elements <b>37</b> positioned along the first and second light emitting element axes <b>46</b> and <b>48</b> in the manner best seen in <figref idref="DRAWINGS">FIG. 5</figref>. However, because persons having ordinary skill in the art would be able to readily provide such additional light emitting elements <b>37</b> after having become familiar with the teachings provided herein, the additional light emitting elements <b>37</b> that may be utilized will not be described in further detail herein.
0030As was briefly mentioned earlier, the first and second light emitting element axes <b>46</b> and <b>48</b> are separated by a spaced-distance <b>50</b> along the direction of the displacement path <b>26</b>. The staggered spacing of the first and second light emitting elements <b>38</b> and <b>40</b> allows the overall length <b>49</b> of the light source assembly <b>30</b> to be reduced compared to what would otherwise be the case if the individual light emitting elements <b>37</b> were aligned along a common axis. The magnitude of the reduced overall length <b>49</b> will be particularly significant in the case where individual collimating lenses <b>41</b> are used for each individual light emitting element <b>37</b>.
0031As was also mentioned earlier, it is noted that the optical encoder <b>10</b> is not limited to use with two light emitting elements <b>37</b>, such as first light emitting element <b>38</b> and second light emitting element <b>40</b>, but instead could comprise any number of light emitting elements <b>37</b>. For example, in the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 4 and 5</figref>, the light source assembly <b>30</b> comprises a total of four light emitting elements <b>37</b>, with two light emitting elements <b>37</b> arranged along the first light emitting element axis <b>46</b> and two light emitting elements <b>37</b> arranged along the second light emitting element axis <b>48</b>. As mentioned, the plurality of light emitting elements <b>37</b> are staggered so as to minimize the overall length <b>49</b> of the light source assembly <b>30</b>.
0032The light emitting elements <b>37</b>, e.g., first and second light emitting elements <b>38</b> and <b>40</b>, may comprise any of a wide range of light emitting devices that are now known in the art or that may be developed in the future that are or would be suitable for the intended application. Consequently, the light emitting elements <b>37</b> should not be regarded as limited to any particular type of light emitting element <b>37</b>. However, by way of example, the plurality of light emitting elements <b>37</b> may comprise light emitting diodes.
0033The various light emitting elements <b>37</b> may be mounted to any of a wide range of structures, such as a printed circuit board, suitable for holding the various light emitting elements <b>37</b> at the proper positions on the first side <b>14</b> of code strip <b>12</b> in the manner described herein. Alternatively, other mounting arrangements are possible, as would become apparent to persons having ordinary skill in the art after having become familiar with the teachings provided herein. By way of example, in one embodiment, the various light emitting elements <b>37</b> are mounted to a printed circuit board <b>68</b> of the type well-known in the art.
0034As mentioned, each light emitting element <b>37</b> (e.g., first light emitting element <b>38</b> and second light emitting element <b>40</b>) may be provided with a separate collimating lens <b>41</b> (e.g., first lens <b>42</b> and second lens <b>44</b>) for collimating the light produced by the light emitting elements <b>37</b>. The collimating lenses <b>41</b> may comprise any of a wide variety of lens shapes and may be fabricated from any of a wide variety of materials, as would become apparent to persons having ordinary skill in the art after having become familiar with the teachings provided herein. Consequently, the collimating lens <b>41</b> should not be regarded as limited to any particular type of collimating lens <b>41</b> fabricated from any particular material. However, by way of example, in one embodiment, each collimating lens <b>41</b> comprises a convex collimating lens fabricated from a transparent plastic material (e.g., acrylic plastic). The collimating lenses <b>41</b> may be provided with suitable mounting lugs or tabs and may be secured to the printed circuit board <b>68</b> by any convenient means, such as, for example, by a suitable adhesive.
0035As best seen in <figref idref="DRAWINGS">FIG. 4</figref>, the staggered arrangement of the light emitting elements <b>37</b>, such as first and second light emitting elements <b>38</b> and <b>40</b>, as well as the corresponding staggered arrangement of the respective collimating lenses <b>41</b>, such as first and second collimating lenses <b>42</b> and <b>44</b>, makes efficient use of space on the printed circuit board <b>68</b> and minimizes the overall length <b>49</b> of the light source assembly <b>30</b> over what would otherwise be the case if the light sources <b>37</b> and lenses <b>41</b> were not staggered.
0036The detector assembly <b>32</b> is best seen in <figref idref="DRAWINGS">FIG. 6</figref> and may comprise a plurality of detector elements <b>51</b>, such as a first detector element <b>52</b> and a second detector element <b>54</b>. The first detector element <b>52</b> is positioned along a first detector element axis <b>56</b>, whereas the second detector element <b>54</b> is positioned along a second detector element axis <b>58</b>. The first and second detector element axes <b>56</b> and <b>58</b> are separated by a spaced-distance <b>60</b> along the direction of the displacement path <b>26</b>. In the embodiment shown and described herein, the spaced-distance <b>60</b> separating the first and second detector element axes <b>56</b> and <b>58</b> is substantially equal to the spaced-distance <b>50</b> between the first and second light emitting element axes <b>46</b> and <b>48</b> (<figref idref="DRAWINGS">FIG. 4</figref>). In addition, the first detector element <b>52</b> is generally aligned with the first track <b>18</b> of the code strip <b>12</b> so that the first detector element <b>52</b> detects the indicia <b>20</b> comprising the first track <b>18</b> of code strip <b>12</b>. The second detector element <b>54</b> is generally aligned with the second track <b>22</b> of code strip <b>12</b> so that the second detector element <b>54</b> detects the indicia <b>24</b> comprising the second track <b>22</b> of code strip <b>12</b>.
0037It should be noted that the optical encoder <b>10</b> is not limited to use with two detector elements <b>51</b>, such as first detector element <b>52</b> and second detector element <b>54</b>, but instead could comprise any number of detector elements <b>51</b>. For example, in the embodiment illustrated in <figref idref="DRAWINGS">FIG. 6</figref>, the detector assembly <b>32</b> comprises a total of eleven (11) detector elements <b>51</b>, with six (6) detector elements arranged along the first detector element axis <b>56</b> and with five (5) detector elements <b>51</b> arranged along the second detector element axis <b>58</b>. The use of eleven (11) individual detector elements <b>51</b> allows a ten track code strip <b>12</b> to be used, with one detector element <b>51</b> per track <b>17</b>. The remaining (11<sup>th</sup>) detector element <b>51</b> is used to measure the intensity or light output of the light source assembly <b>30</b>. If the intensity of the light source assembly <b>30</b> is too high or too low, a compensation system (not shown) may be used to adjust the electrical power provided to the light source assembly <b>30</b>, thereby maintaining the light output within acceptable limits. A ten track code strip <b>12</b> will provide a resolution of 2<sup>10 </sup>or 1024 discrete positions. Of course, a greater or lesser number of detector elements <b>51</b> and code strip tracks <b>17</b> could be used depending on the requirements of the particular application. Examples of requirements that would indicate the use of a code strip having a greater or lesser number of tracks <b>17</b> include, but are not limited to, the desired resolution as well as the range of motion that is desired to be encoded.
0038The staggered spacing of the various detector elements <b>51</b> (e.g., <b>52</b> and <b>54</b>) comprising the detector assembly <b>32</b>, i.e., the fact that the second detector element axis <b>58</b> is located the spaced-distance <b>60</b> along the displacement path <b>26</b> from the first detector element axis <b>56</b>, means that the indicia <b>24</b> comprising the second track <b>22</b> of the code strip <b>12</b> should be displaced or off-set by substantially the same distance, i.e., the spaced-distance <b>60</b>.
0039The detector elements <b>51</b>, e.g., first and second detector elements <b>52</b> and <b>54</b>, may comprise any of a wide range of light detecting devices that are now known in the art or that may be developed in the future that are or would be suitable for the intended application. Consequently, the light detecting element <b>51</b> should not be regarded as limited to any particular type of light detecting element <b>51</b>. However, by way of example, the plurality of light detecting elements <b>51</b> may comprise photo-transistors.
0040The various detector elements <b>51</b> may be mounted to any of a wide variety of structures, such as printed circuit boards, suitable for holding the various detector elements <b>51</b> at the proper positions on the second side <b>16</b> of code strip <b>12</b> in the manner described herein. Alternatively, other mounting arrangements are possible, as would become apparent to persons having ordinary skill in the art after having become familiar with the teachings provided herein. By way of example, in one embodiment, the various light detecting elements <b>51</b> are mounted to a printed circuit board <b>70</b>.
0041The optical encoder <b>10</b> may also be provided with an aperture plate <b>62</b>. The aperture plate <b>62</b> defines at least one aperture for each of the detector element axes (e.g., first detector element axis <b>56</b> and second detector element axis <b>58</b>) utilized on the detector assembly <b>32</b>. In the embodiment shown and described herein, the aperture plate <b>62</b> defines at least a first aperture <b>64</b> that is substantially aligned with the first detector element <b>52</b> on the first detector element axis <b>56</b> and a second aperture <b>66</b> that is substantially aligned with the second detector element <b>54</b> on the second detector element axis <b>58</b>. Additional apertures may be provided for each grouping of detector elements <b>51</b> that may be provided on the detector assembly <b>32</b>. Generally speaking, it will be desirable to form the first and second apertures <b>64</b> and <b>66</b> as elongated slits in order to minimize the chances that stray light will reach the detector elements <b>51</b>.
0042Depending on the particular application, the aperture plate <b>62</b> may also be used to increase the resolution of the optical encoder system over what would otherwise be possible without the aperture plate <b>62</b>. For example, if the spacings between the various indicia <b>19</b> provided on the tracks <b>17</b> of the code strip <b>12</b> are smaller than the size of the corresponding detector element <b>51</b>, then the detector element <b>51</b> would be incapable of resolving the spacing between the indicia <b>19</b>. That is, the detector <b>51</b> would not be capable of isolating which set of indicia was positioned directly in line with the detector element <b>51</b>. In order to avoid this problem, the aperture plate <b>62</b> may be provided with an aperture having a size (i.e., width) that is substantially equal to the width of the indicia <b>19</b> on the code strip <b>12</b>. The aperture would then prevent light from other indicia <b>19</b> from reaching the detector element <b>51</b>, thereby allowing the detector element <b>51</b> to sense only the desired portion of the code strip <b>12</b>. Stated another way, the detector element <b>51</b> will then be able to detect a single indicia <b>19</b> on the code strip <b>12</b>, notwithstanding the fact that the size (i.e., width) of the detector element <b>51</b> exceeds the size (i.e., width) of the indicia <b>19</b> on the code strip <b>12</b>.
0043The housing <b>34</b> may be configured to receive the light source assembly <b>30</b>, the detector assembly <b>32</b>, as well as the aperture plate <b>62</b>. Referring now to <figref idref="DRAWINGS">FIGS. 2</figref>, <b>7</b><i>a</i>, <b>7</b><i>b</i>, and <b>8</b>, the housing <b>34</b> may comprise a detector plate portion <b>72</b> and an emitter plate portion <b>74</b>. The detector plate portion <b>72</b> is configured to receive the detector assembly <b>32</b> as well as the aperture plate <b>62</b>. The emitter plate portion <b>74</b> is configured to receive the light source assembly <b>30</b>. The emitter plate portion <b>74</b> is securable to the detector plate portion <b>72</b> and holds or positions the light source assembly <b>30</b> so that it is generally aligned with the detector assembly <b>32</b>. The housing <b>34</b> also positions the light source assembly <b>30</b> and detector assembly <b>32</b> so that a space <b>36</b> is defined therebetween suitable for receiving the code strip <b>12</b>.
0044The component spacings provided by the housing <b>34</b> are not particularly critical, and any of a wide range of spacing may be used depending on the particular application. Consequently, the housing <b>34</b> should not be regarded as limited to a housing providing any particular spacing between the optical encoder's various components. However, by way of example, in the embodiment shown and described herein, the space <b>36</b> defined between the light source assembly <b>30</b> and the detector assembly <b>32</b> is about 6.25 mm; the code strip <b>12</b> is positioned about 1.9 mm from printed circuit board <b>70</b> of the detector assembly <b>32</b>; and the aperture plate <b>62</b> is positioned about 1.23 mm from the printed circuit board <b>70</b> of the detector assembly <b>32</b>. See <figref idref="DRAWINGS">FIG. 3</figref>.
0045With reference now to <figref idref="DRAWINGS">FIGS. 7</figref><i>a</i>, <b>7</b><i>b</i>, and <b>8</b>, the detector plate portion <b>72</b> of housing <b>34</b> may comprise a plurality of bearing surfaces <b>76</b> provided thereon. The bearing surfaces <b>76</b> engage corresponding first and second edge portions <b>78</b>, <b>80</b> of code strip <b>12</b>. The bearing surfaces <b>76</b> help to position the code strip <b>12</b> an optimal distance from the detector assembly <b>32</b> and aperture plate <b>62</b>, as well as to minimize the likelihood that the code strip <b>12</b> will contact either the light source assembly <b>30</b>, the detector assembly <b>32</b> or aperture plate <b>62</b>.
0046The bearing surfaces <b>76</b> may comprise any of a wide range of shapes and configurations, as would become apparent to persons having ordinary skill in the art after having become familiar with the teachings provided herein. Consequently, the bearing surfaces <b>76</b> should not be regarded as limited to bearing surfaces <b>76</b> having any particular shapes or configurations. However, by way of example, in one embodiment, each bearing surface <b>76</b> comprises a generally semi-cylindrical surface.
0047The various components (e.g., detector plate portion <b>72</b> and emitter plate portion <b>74</b>) comprising the housing <b>34</b> may be fabricated from any of a wide range of materials that would be suitable for the intended application. By way of example, in one embodiment, the detector plate portion <b>72</b> and emitter plate portion <b>74</b> are molded from a polycarbonate plastic material. Alternatively, other materials could also be used.
Contents5
7 sheets
Sheet 1 Sheet 2 Sheet 3 Sheet 4 Sheet 5 Sheet 6 Sheet 7
Every citation, both ways
| Document | Relation | Office | Cited during |
|---|---|---|---|
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| US2018031359A1 | Cited by | United States of America | Pre-grant |
| US2018031359A1 | Cited by | United States of America | Search report |
| US10352675B2 | Cited by | United States of America | Search report |
| US7795576B2 | Cited by | United States of America | Applicant |
| US2010155586A1 | Cited by | United States of America | Pre-grant |
| US2010314532A1 | Cited by | United States of America | Pre-grant |
| US8193483B2 | Cited by | United States of America | Applicant |
| US8173950B2 | Cited by | United States of America | Applicant |
| EP0365740A1 | Cites | European Patent Office (EPO) | Applicant |
| EP0365740A1 | Cites | European Patent Office (EPO) | Applicant |
| EP0365740A1 | Cites | European Patent Office (EPO) | Applicant |
| US2004113058A1 | Cites | United States of America | Search report |
| US2006145065A1 | Cites | United States of America | Applicant |
| AT396840B | Cites | Austria | Applicant |
| AT396840B | Cites | Austria | Applicant |
| US4360730A | Cites | United States of America | Search report |
| US4508965A | Cites | United States of America | Search report |
| US4680466A | Cites | United States of America | Search report |
| US5065012A | Cites | United States of America | Search report |
| US5091643A | Cites | United States of America | Search report |
| US5235177A | Cites | United States of America | Applicant |
| US5428217A | Cites | United States of America | Applicant |
| US5698851A | Cites | United States of America | Search report |
| US5701007A | Cites | United States of America | Search report |
| US5808730A | Cites | United States of America | Applicant |
| US6093928A | Cites | United States of America | Applicant |
| US6255644B1 | Cites | United States of America | Search report |
| US6800842B2 | Cites | United States of America | Applicant |
| US20040113058A1 | Cites | United States of America | Search report |
| US20060145065A1 | Cites | United States of America | Third party observation |
| AT396840B | Cites | Austria | Third party observation |
| AT396840 | Cites | Austria | Third party observation |
| EP365740A1 | Cites | European Patent Office (EPO) | Third party observation |
| EP365740 | Cites | European Patent Office (EPO) | Third party observation |
| English translation of Abstract of EP 0365 740 A1. | Non-patent | – | Applicant |
| English translation of Abstract of AT 396 840 B. | Non-patent | – | Applicant |
| UK Office Action of Apr. 26, 2006 for UK patent application corresponding to U.S. Appl. No. 11/031,280. | Non-patent | – | Applicant |
| Agilent Technologies, "Two Channel High Resolution Optical Incremental Encoder Modules", May 8, 2002, 11 pages. | Non-patent | – | Applicant |
| Agilent Technologies, "Agilent AEDS-962x for 300 LPI Ultra Small Optical Encoder Modules", Nov. 26, 2002, 10 pages. | Non-patent | – | Applicant |
| Thomas E. Kissell, "Linear and Rotary Encoders", at least as early as Nov. 19, 2004, 5 pages. | Non-patent | – | Applicant |
| "English translation of Abstract of", EP 0365740A1. | Non-patent | – | Applicant |
| "English translation of Abastract of", AT 396 840 B. | Non-patent | – | Applicant |
| "UK Office Action of Apr. 26, 2006". | Non-patent | – | Applicant |
| Agilent Technologies, "Two Channel High Resolution Optical Incremental Encoder Modules", www.agilent.com/semiconductors, (May 8, 2002), 11 pages. | Non-patent | – | Applicant |
| Agilent Technologies, "Agilent AEDS-962x for 300 LPI Ultra Small Optical Encoder Modules", www.agilent.com/semiconductors, (Nov. 26, 2002), 10 pages. | Non-patent | – | Applicant |
| Kissell, Thomas E., "Linear and Rotary Encoders", www.zone.ni.com, (at least as early as Nov. 19, 2004), 5 pages. | Non-patent | – | Applicant |
| English translation of Abstract of EP 0365 740 A1. | Non-patent | – | Third party observation |
| English translation of Abstract of AT 396 840 B. | Non-patent | – | Third party observation |
| UK Office Action of Apr. 26, 2006 for UK patent application corresponding to U.S. Appl. No. 11/031,280. | Non-patent | – | Third party observation |
| Agilent Technologies, “Two Channel High Resolution Optical Incremental Encoder Modules”, May 8, 2002, 11 pages. | Non-patent | – | Third party observation |
| Agilent Technologies, “Agilent AEDS-962x for 300 LPI Ultra Small Optical Encoder Modules”, Nov. 26, 2002, 10 pages. | Non-patent | – | Third party observation |
| Thomas E. Kissell, “Linear and Rotary Encoders”, at least as early as Nov. 19, 2004, 5 pages. | Non-patent | – | Third party observation |
| “English translation of Abstract of”, EP 0365740A1. | Non-patent | – | Third party observation |
| “English translation of Abastract of”, AT 396 840 B. | Non-patent | – | Third party observation |
| “UK Office Action of Apr. 26, 2006”. | Non-patent | – | Third party observation |
| Agilent Technologies, “Two Channel High Resolution Optical Incremental Encoder Modules”, www.agilent.com/semiconductors, (May 8, 2002), 11 pages. | Non-patent | – | Third party observation |
| Agilent Technologies, “Agilent AEDS-962x for 300 LPI Ultra Small Optical Encoder Modules”, www.agilent.com/semiconductors, (Nov. 26, 2002), 10 pages. | Non-patent | – | Third party observation |
| Kissell, Thomas E., “Linear and Rotary Encoders”, www.zone.ni.com, (at least as early as Nov. 19, 2004), 5 pages. | Non-patent | – | Third party observation |
11 members in 5 offices
Priority claims6
| Document | Office | Kind | Date |
|---|---|---|---|
| 3128005 | United States of America | A | |
| 3128005 | United States of America | A | |
| 75782607 | United States of America | A | |
| 11031280 | – | – | – |
| US20050031280 | – | – | – |
| US20070757826 | – | – | – |
Members11
| Document | Office | Kind | |
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| GB0600092D0 | United Kingdom | D0 | |
| CN1800788A | China | A | |
| GB2422007A | United Kingdom | A | |
| US2006151686A1 | United States of America | A1 | |
| TW200624979A | Taiwan Province of China | A | |
| JP2006189449A | Japan | A | |
| US7244928B2 | United States of America | B2 | |
| US2007221831A1 | United States of America | A1 | |
| US7449677B2This record | United States of America | B2 | |
| GB2422007B | United Kingdom | B | |
| CN100529678C | China | C |
48 transactions on the USPTO file
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| Date Forwarded to ExaminerFWDX | FWDX | |
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| Electronic ReviewELC_RVW | ELC_RVW | |
| Email NotificationEML_NTF | EML_NTF | |
| Mail Non-Final RejectionNon-final rejectionMCTNF | MCTNF | |
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| Information Disclosure Statement (IDS) FiledM844 | M844 | |
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| Case Docketed to Examiner in GAUDOCK | DOCK | |
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| Cleared by OIPE CSRL194 | L194 | |
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| Initial Exam Team nnIEXX | IEXX |
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| Lapsed due to failure to pay maintenance feeLapsedFP | FP | |
| Information on status: patent discontinuationPATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362STCH | STCH | |
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| Maintenance fee reminder mailedREMI | REMI |
Numbers
- Publication
- 07449677
- Publication, DOCDB
- 7449677
- Publication, EPODOC
- US7449677
- Application
- 11757826
- Application, DOCDB
- 75782607
- Application, EPODOC
- US20070757826
Titles
- English
- Optical encoder
Patent term adjustment
- Net adjustment
- 0 days
Classification
- CPC, 4
- G01D5/34746
- G01D5/34715
- G01D5/347
- G01D5/34707
- IPC, 1
- G01D5 34
- USPC, 2
- 250231140
- 250231130